re 124gr GDHP and n340 in my Sig 239: Well, I ran some chrono checks last week and got screwy results (lower bullet speeds) in bright sunshine.
So Sat. I loaded up a few more to a hotter load I don't need to mention., went to the range and DUH!!, didn't have the chrono in my truck.
I shot a few anyway, and they were snappy, not as soft as previous editions. A very noticeable change with .2 grains more powder at the same oal.
The primers (Federal SPP) were dead flat, but not flowing around the FP ding, just flat-flat. I tried to take some pics, but couldn't get it to show up.
You really can't see that the primers are really flattened, but not otherwise distorted.
I plan to go again--this time WITH the chronograph and find out the mach number of these birds.
Hot rounds are new for me. This IS a hot round, maybe too hot. I'll find out out more Tues and will have a few more to try out on a target.
I may zing a couple out of my 75B to see the speed difference in the longer bbl. (Gun abuse!)